!! History Commons Alert, Exciting News

Context of '(10:00 a.m.) September 11, 2001: Flight 93’s Autopilot Turned Off; Alarms Sound'

This is a scalable context timeline. It contains events related to the event (10:00 a.m.) September 11, 2001: Flight 93’s Autopilot Turned Off; Alarms Sound. You can narrow or broaden the context of this timeline by adjusting the zoom level. The lower the scale, the more relevant the items on average will be, while the higher the scale, the less relevant the items, on average, will be.

After leveling off at 25,000 feet and making a slight course change to the east-northeast, Flight 77 has its autopilot disconnected. It remains off for about three minutes before being re-engaged. This is according to information later obtained from its flight data recorder. During these three minutes, Flight 77’s altitude dips as low as 22,000 feet, but by the time the autopilot is re-engaged it has leveled again at 25,250 feet. [National Transportation Safety Board, 2/13/2002, pp. 3 pdf file; National Transportation Safety Board, 2/19/2002, pp. 2 pdf file; 9/11 Commission, 8/26/2004, pp. 30 and 94] The autopilot will later be disengaged again for the last eight minutes of the plane’s flight (see 9:29 a.m. September 11, 2001).

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Flight 77’s autopilot is disengaged. The plane is flying at 7,000 feet and is about 38 miles west of the Pentagon. [9/11 Commission, 7/24/2004, pp. 9] Information from the plane’s recovered flight data recorder (see September 13-14, 2001) later will indicate the pilot had entered autopilot instructions for a course to Ronald Reagan Washington National Airport (which is nearby the Pentagon). [9/11 Commission, 1/27/2004]

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Based on information from the plane’s flight data recorder, the National Transportation Safety Board will later determine that Flight 93’s autopilot is turned off at “about 10:00,” and remains off for the flight’s final minutes. [National Transportation Safety Board, 2/13/2002 pdf file] Phil Bradshaw, whose wife is an attendant on Flight 93, will later hear the plane’s cockpit voice recording. Being a pilot himself, he recognizes on it the sound of the alarm that goes off when the autopilot is disconnected. [News and Record (Piedmont Triad, NC), 9/11/2002] CNN’s Kelli Arena will hear the recording during the 2006 Zacarias Moussaoui trial and will report that, shortly after this alarm sounds, “Another alarm goes off.” [CNN, 4/12/2006] According to journalist and author Jere Longman, as well as the alarm set off when the autopilot was disconnected, another alarm “would have sounded because the plane was traveling at five hundred seventy-five miles an hour in the final minutes, far exceeding the design limits of four hundred twenty-five miles an hour below twenty thousand feet and two hundred eighty-seven miles an hour below ten thousand feet.” [Longman, 2002, pp. 208] So presumably this is the second alarm described by Arena.

Entity Tags: RobertMoomo, Jere Longman, Kelli Arena, Phil Bradshaw

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Flight 93’s transponder, which was switched off after Flight 93 was hijacked, is turned back on just before the plane crashes, thereby revealing the plane’s altitude to air traffic controllers at the FAA’s Cleveland Center. [Federal Bureau of Investigation, 9/11/2001; MSNBC, 9/11/2002] A transponder is a device that sends a plane’s identifying information, speed, and altitude to controllers’ radar screens. [Washington Post, 9/16/2001] Flight 93’s transponder was switched off at around 9:40 a.m. (see (9:40 a.m.) September 11, 2001), although Cleveland Center controllers have still been able to follow Flight 93 on “primary radar,” which shows less information about a flight (see (9:41 a.m.-10:06 a.m.) September 11, 2001). [Federal Bureau of Investigation, 1/8/2002; 9/11 Commission, 7/24/2004, pp. 29; Cleveland Plain Dealer, 7/3/2011]
Plane Shown to Be Flying at 8,200 Feet - Flight 93’s transponder is reactivated at 10:02 a.m. and 50 seconds, and then stays on for “approximately 20 seconds,” according to “information from the flight data” provided to the FBI later today by Rick Kettell, the manager of the Cleveland Center. After the transponder is turned back on, Flight 93’s radar track is observed by Cleveland Center controllers Linda Justice and Stacey Taylor. The information from the transponder shows them that Flight 93 is at an altitude of 8,200 feet. [Federal Bureau of Investigation, 9/11/2001; Federal Aviation Administration, 9/16/2001 pdf file; 9/11 Commission, 10/2/2003 pdf file]
Plane Soon Disappears from Radar Screens - Flight 93 will crash into the ground at 10:03 a.m. and 11 seconds, according to the 9/11 Commission Report, less than 30 seconds after the transponder is reactivated (see (10:03 a.m.-10:10 a.m.) September 11, 2001). [9/11 Commission, 7/24/2004, pp. 30] Cleveland Center controllers will see the plane completely disappear from their radar screens around that time. [MSNBC, 9/11/2002] A Cleveland Center controller will then report, apparently over an FAA teleconference, that Flight 93’s transponder “came on briefly and then it went back off with the primary, and now we’ve lost him completely.” [Federal Aviation Administration, 9/11/2001] “I had two radar hits on [Flight 93],” Taylor will recall, adding that she then “lost the primary target on [Flight 93] and we suspected it had gone down.” [Federal Aviation Administration, 9/16/2001 pdf file] The reason Flight 93’s transponder is switched back on just before the plane crashes is unclear. Taylor will comment, a year after 9/11: “That’s something we’ve always wanted to know. Why did the transponder come back on?” She will say Cleveland Center controllers wondered this because they believed that “the hijackers had shut it off so that they couldn’t be tracked.” [MSNBC, 9/11/2002]

Entity Tags: Stacey Taylor, Cleveland Air Route Traffic Control Center, Linda Justice

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

It is initially reported that Flight 93 was traveling fairly slowly when it crashed on September 11. Days after the attacks, the New York Times reports that Flight 93 “slammed into the ground at a speed that law enforcement authorities said might have approached 300 miles an hour.” [New York Times, 9/14/2001] Another newspaper reports, “Flight 93 slammed into the earth nose-first at over 200 mph, according to estimates by the National Transportation Safety Board and other experts.” [News Journal (Wilmington, DE), 9/16/2001] However, by 2002 it is being reported that the plane crashed going nearly 600 mph. [Longman, 2002, pp. 212] “It could have even broken the sound barrier for a while,” says Hank Krakowski, who was United Airlines’ director of flight operations on September 11. [New York Times, 3/27/2002] The design limits of the plane are 287 mph when flying below 10,000 feet. [Longman, 2002, pp. 208]

Entity Tags: RobertMoomo, Hank Krakowski

Timeline Tags: Complete 911 Timeline, 9/11 Timeline

Ordering 

Time period


Email Updates

Receive weekly email updates summarizing what contributors have added to the History Commons database

 
Donate

Developing and maintaining this site is very labor intensive. If you find it useful, please give us a hand and donate what you can.
Donate Now

Volunteer

If you would like to help us with this effort, please contact us. We need help with programming (Java, JDO, mysql, and xml), design, networking, and publicity. If you want to contribute information to this site, click the register link at the top of the page, and start contributing.
Contact Us

Creative Commons License Except where otherwise noted, the textual content of each timeline is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike